Retractable blast deflector and acoustic barrier



L. H. KLEIN July 21, 1964 2 Sheets-Sheet 1 Filed April 1o, 1962 wm@ N Qi@ m H m T L 7 n m K f WH M m QN V, S N A w M, c, s 0 n A L Q w\\ m E W A m.. W 5

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L.. H. KLEIN 3,141,639

RETRACTABLE BLAST DEFLECTOR AND ACOUSTIC BARMER Filed April l0, 1962 2 Sheets-Sheet 2 July 21, 1964 N l 4 1 H l 1 4 l I l l| l.. l| 3 1 .u l Il m. nm rE O K 7 v n m 1 E o V H N M .l S 14 l m x U m O 7 0 l I|| l||L .|||L :1?41 Y J8 B 0 6 L l HH .\I ..||n.u H Twlll H Nv 2 Ov 7 /Ln 0 0 ou Mll u H mnlllllh H IIJ-M1 l my ,v F 8 U. f 1. n n n" E El/V l l|| I 1 -1 l.- L F United States Patent O 3,141,639 RETRACTABLE BLAST DEFLECTOR AND ACOUSTEC BARRIER Louis H. Klein, 1328 Vista Grande, Milbrae, Calif., as-

signor of one-third to Marit Falk and one-third to Corwin Booth, both of San Francisco, Calif.

Filed Apr. 10, 1962, Ser. No. 136,382 13 Claims. (Cl. 244-114) This invention relates to a blast deiiector and acoustic barrier, and has for one of its objects the provision of a barrier adapted to deflect the blasts and noise from airplane engines.

With the advent of jet propelled airplanes the rearwardly directed blasts and noise generated by the engines at starting points at landing fields, and at test stands, has not only become highly objectionable to persons living or working in a fairly close vicinity to the landing fields and test stands, but has resulted in injury to the health of such persons, and in damage to their property.

One of the expedients proposed for restricting the blasts and noise has been to plant trees as a barrier. Others have proposed erecting walls. Neither suggestion has received acceptance. Obviously the use of trees, apart from the time required for their growth, results in permanence that precludes the making of changes to meet changing conditions, and both trees and walls of the type suggested, create hazards to the airplanes using the landing elds.

One of the main objects of this invention is the provision of a blast deiiector and acoustic barrier that is adapted to effectively deflect the blasts and noise from airplane engines and which detlector and barrier is adapted to be quickly retracted, when not in use, so as to completely clear the area occupied by the detlector and barrier for use by vehicles of any type including aircraft on the ground. i

Another and serious objection to the use of walls and trees is the hazard they present to the landing and taking off of aircraft.

An object of this invention is the provision of retractable blast deiiectors and acoustic barriers that are erected only when the airplane is in a position to take off, or is at a testing stand, hence the barriers offer substantially no greater hazard to aircraft that is landing than the airplane that is at the barrier.

A still further object is the provision of a retractable wall that may be retracted or erected while the airplane is in a take-off position or is at the test stand.

Another object of the invention is the provision of retractable blast detlectors and acoustic barrier construction that is adapted to accommodate airplanes of different sizes. In explanation of this, the present deiiector and barrier may comprise separable walls that may be selectively erected and retracted according to the size of the airplane, or the number, and also the walls in some instances are arranged in an accurate row with the airplane positioned at the concave or inner side of the curve, in which case each wall virtually forms a chord of the arc.

A still further object of the invention is the provision of a blast deector and acoustic barrier that is constructed and arranged to more effectively deflect the blasts and noise than heretofore, and which deector and barrier is rugged, economical to make and of relatively simple structure, and that is adapted to be moved to a collapsed position when not in use, in which collapsed position it does not interfere with traic on the ground.

Other objects and advantages will appear in the description and drawings.

In the drawings, FIG. 1 is a side elevational view of ice the deiiector and barrier in collapsed position in a pit, with dot-dash lines showing the dellector` in elevated position. The ground and pit walls are indicated in cross section.

FIG. 2 is a cross sectional view at line 2-2 of FIG. l showing one Wall section and a portion of an adjacent wall.

FIG. 3 is an end elevational View taken along line 3-3 of FIG. 1, part of the pit wall and ground being shown in cross section.

PIG. 4 is an enlarged, fragmentary cross sectional view at the juncture between a pair of adjacent walls.

FIG. 5 is a top elevational view of a deliector and barrier partly broken away for clarity.

FIG. 6 is a slightly modified view showing an hydraulic system for raising and lowering a wall.

FIG. 7 is a modication of FIG. 6, also using an hydraulic system.

FIG. 8 is a semidiagrarnmatic plan view of an arcuate row of walls or deilectors.

Referring to FlG. l each deflector and barrier unit comprises an upper wall, generally designated 1, and a lower wall generally designated 2. These walls are shown in full line in FIG. l in a collapsed, inoperative position within a pit 3 that is formed in the ground, and that may have concrete walls 4.

Each upper wall 1 includes a coplanar extension 5 and in the form illustrated this extension may be of the same structure as that of the upper wall. The combined wall and extension are illustrated as being oblong, hence elongated in one dimension. Therefore reference to structure extending longitudinally of the wall refers to structure extending lengthwise thereof, or from one end of extension 5 to the opposite upper end of the upper wall section 1. However, it is to be understood that the Wall and its extension 5 could be substantially square, and of greater width than vertical length, using the same arrangement of structural elements.

The upper wall 1 and its extension 5 have an upper covering 7 (FIG. 2) which may be of any suitable metal, and the free edges of the legs of T beams 8 are preferably welded to the underside of the cover plate 7. Thus the T beams will depend from the cover plate 7 and these beams are preferably equally spaced from each other and extend longitudinally of the upper wall 1. Along each of the longitudinally extending lateral edges of the upper cover plates 7 are I beams 9, instead of the T beams, and these are parallel with the T beams and spaced therefrom and are welded to the two opposite longitudinally extending marginal portions of cover plate 7.

Material strips ylil (FIG. l) extend between adjacent pairs of T beams and between the I beams and the adjacent T beams at points spaced longitudinally of the beams, which strips may be welded to the cover plate and beams.

Channel strips 12, 13 extend across the opposite ends of the T and I beams at opposite ends of the upper wall 1 and may be welded to said beams and to the marginal portions of the cover plate 7 at each end of the wall 1 (which includes extension 5). These channel strips 12, 13 are of greater vertical width than the T and I beams S, 9. The channel strip 12, which is shown at the lefthand end of the extension 5, carries bearings rotatably supporting a pair of wheels or rollers 14.

Two pairs of said rollers are shown in FIG. 3, the rollers of each pair being supported on a horizontally extending track 15 at opposite sides of a central upstanding rib extending longitudinally of each track. Obviously this particular structure may be varied. Said pairs of rollers are spaced to most eiiiciently support the load ofthe walls.

The tracks 15 may be in the pit 3, and supported and secured on suitable concrete supports, and the channel strip 13 at the end of the upper wall opposite to the wheels or rollers 14 may rest on a lportion of the concrete 4 when the walls are in retracted or collapsed position. Lower wall 2 may be approximately the same length as the upper wall 1 from approximately the juncture between upper wall ll and extension thereof outwardly, and the structure of the lower wall is substantially the same as that of the upper wall, except that the covering 17 on the lower wall is lowermost and the T beams 18 are on the upper side thereof, as seen in FIG. 2. Also, there may be fewer T beams on wall 2, since it is not required to provide for superimposed loads thereon.

The legs of the T beams 1S are positioned between alternate pairs of beams on the upper wall, and at approximately midway between the ends of the upper wall 1 a bar 19 extends through the legs of the beams S, 9, 18 to pivotally connect one end of lower wall 2 with the upper wall 1 for swinging of the upper and lower walls relative to each other about the horizontal axis of the bar 19.

The upper wall 1 overlies the lower wall 2 when the walls are in collapsed, substantially horizontally disposed relation, and the end of wall 2 opposite to bar 19 terminates at apoint adjacent to, preferably slightly short of the channel strip 13 that is at the end of wall 1. A horizontal bar 21 at the outer end of wall 2, which is the end adjacent to channel strip 13, may be carried by bearings or brackets 22 secured to the concrete wall 4 of the pit 3 for pivotally supporting said outer end of wall 2 to enable upward swinging of the opposite end thereof. The lower wall 2 extends slightly slantingly downwardly from the bar 19 toward the pivot 21, hence the wall 2 is preferably at a slight angle to wall 1. This is, of course, when the walls are in retracted or collapsed position.

A central T beam `23 extending transversely of the T beams 8 is welded to the cover plate 7 and projects below the lower level of said beam 8 for resting on a concrete support 24 when the walls 1, 2 are in collapsed position (FIG. 1).

From the foregoing description, it will be seen that by applying a force on the end of extension 5 of wall 1, toward the opposite end of the wall 2, the walls 1 and 2 will swing upwardly to the erected position shown in dot-dash lines (FIG. l). In this erected position the upper wall 1 and lower wall 2 extend angularly relative to each other with said walls oppositely inclined to one side of a vertical plane from the pivotal connection between said walls forming a reentrant angle at the sides of the walls having the T beams secured thereto. The surfaces of the walls carrying the T beams face oppositely to the direction from which the engine blasts are to come. Hence the beams on the walls form channels into which the blasts are received.

Several diferent means may be employed to elevate the walls 1, 2. One such means is illustrated in FIG. 1, in which one or more wire ropes 20 may be connected with the end of the upper wall 1 that is adjacent to the rollers 14. Each rope may extend over a sheave 25 that, in turn, is supported on a wall of pit 3 that is opposite to rollers 14. From each sheave 25 each wire rope extends over a motor driven drum 26 that is supported in pit 3.

Upon actuation of the motor 27 that rotates the drum 26, the outer end of wall 1 that is opposite to rollers 14 will automatically swing upwardly, and beguided by the wall 2 that moves upwardly with wall 1 to the position of walls 1, 2 as seen in FIG. l in dot-dash line. Where this structure is used, it is preferable that an hydraulically actuated booster be employed to start the upward movement of the walls so that motor 27 connected with drum 26 will not be compelled to pick up the entire load from a dead stop.

This hydraulically actuated booster may take any one of several forms. In FIG. l it is indicated as being a vertically disposed cylinder 28, the plunger 29 of which carriers a roller 3@ that, in turn, engages the under side of wall 2 at approximately the point where walls 1, 2 are pivotally connected.

Any suitable means may be provided for actuating the lbooster, such as a solenoid actuated valve 31 in a fluid pressure line 32 that is connected with the cylinder 28. Upon actuation of the valve in one direction the fluid, under pressure will elevate the plunger 29 to thereby commence upward movement of the walls, and upon movement of the valve in the opposite direction the fluid will retain the plunger elevated, until the motor 27 is reversed to lower the walls, and when the wall assembly engages the roller 30 on the plunger, the liquid in the cylinder 28 will be discharged through the solenoid actuated valve past a preset relief valve 33 that will control the discharge of the liquid in the cylinder to the reservoir that supplies uid to the uid pressure line through a conventional pressure pump (not shown). Thus the booster functions as a shock absorber that will cushion the movement of the walls 1, 2 to fully retracted, horizontally disposed position.

It is obvious that any number of boosters may be used with any wall assembly and any number of wire ropes and drums may be employed according to the size of the walls. Also the solenoid actuated valve 31 may be in a conventional switch controlled circuit in series with motor 27 so that the booster will have started raising the walls by the time motor 27 is actuated, whereby the starting load on the motor will be substantially reduced.

Any conventional limit switch 34 may be employed, and adjustably positioned on or adjacent to a track 15, or elsewhere to control motor 27 and solenoid 31 to stop the walls at the desired elevated position. Obviously the weight of the walls would be adequate to enable automatic lowering of the walls under the control of a conventional brake on the drum 26 or a reversal of motor 27, upon release of the drum brake or lock, either of which is conventional.

When walls 1, 2 are in their collapsed or retracted position, the upper wall 1, including extension thereof, is supported at its marginal portions on the pit walls, and the flat upper surface of the ground so that trucks and other ground vehicles, or airplanes, may be supported thereon or pass thereover.

In FIG. 6 instead of the wire rope and drum arrangement for raising and lowering the walls a horizontally disposed hydraulic cylinder 37 is positioned in a continuation of pit 3 at the end of the wall 4 adjacent to the track supported rollers 14, and the plunger 38 of this cylinder is connected with a bracket 39 secured to the end channel strips 12. Several cylinders and plungers may be connected with the upper wall 1, if desired, and these, of course, are connected for simultaneous operation. In many respects an hydraulically actuated lifting means is preferable to the use of the wire rope and motor arrangement, since the hydraulic cylinder or cylinders will dampen the downward movement of the walls, and the booster cylinder may be eliminated.

It should be noted, as seen in FIG. 7, that the lower wall indicated at 4?. may be connected at its outer end with a hydraulically actuated plunger 43 that is in a cylinder 44 instead of being pivotally connected to a stationary bracket, such as 22 in FIG. l. Rollers 45 on the outer end of the lower wall 42 would be supported on tracks 46.

The extension 47 of the upper wall 48 would be pivotally connected at 49 with stationary brackets on the pit wall. Thus upon actuation of the plunger 43 the walls would be erected to the same erected position as seen in FIG. l. It will be seen from the above that the hydraulically actuated means for elevating and for controlling the lowering ofthe walls may be positioned on i either side of the pit that receives the walls, according to which is most convenient.

ln either FIG. 6 or FlG. 7, the excavation for each hydraulic ram is covered by a plate, such as at 51 (FIG. 6), so there will be no open ditches or excavations, and vehicles on the ground can be supported on or freely move over the plates 51.

FIG. 8 is a plan view of a starting point for airplanes in which the walls of the present invention are arranged in an arcuately extending row so that the row of walls extends partially around the airplane, the latter being indicated at 53. In this arrangement each wall assembly is indicated at 54 and the lateral edges of the walls are slightly tapered, longitudinally thereof, instead of being parallel, so that the adjacent edges of adjacent walls will substantially come together. To prevent any cracks or openings between adjacent walls, a flexible strip 55 of material such as belting is secured along and projects outwardly of each edge so as to move to lapping relation (FiG. 4) when the walls are in erected position. These strips 55 are on both the upper and lower walls. Whether the wall assemblies are in straight or curved angularly positioned rows, the above sealing structure may be used for the walls of each adjacent pair thereof.

inasmuch as the number of wall assemblies, or the number of assemblies of deilectors and barriers, may depend upon the location of the test stand or starting point, and upon the size of the airplane that is being started or tested, it is desirable that one or any desired group of wall assemblies be selectively actuatable as desired. ln FlG. 8 the hydraulic erecting means, such as indicated in FG. 6, is shown and each hydraulic pressure line may have a solenoid actuatable two-way valve 56 therein, the solenoid 57 of which is connected with a manually actuatable switch button 53 of a control board 59. By this arrangement all of the walls of the deflector barrier assemblies may be simultaneously elevated, or any assembly of walls 1, 2 or group thereof may be selectively erected or lowered. By this arrangement the actuation of the walls from the control tower is possible, so that none of the walls would be erected unless it were safe to do so with respect to incoming or outgoing airplanes, and also any erected walls could be retracted should they become hazardous to either air or ground trac.

By the wall structure, and their arrangement, so that the ribs or T beams project to the side that faces the airplane, the spill of lthe blast past the lateral edges is materially reduced, and also the noise. This is because the blast and noise is constrained to a large degree to follow the channels, the side of which are formed by the T beams. Also, the height of the lower wall 2 is preferably higher than the maximum height of the engines on the airplanes, so that the blasts from the engines will engage the lower wall and be deflected against the upper wall for deflection backward generally toward the airplane.

Because the extensions 5 or 47 of the upper walls 1 or 4d do not receive the blasts directly from the airplane engines, it is not essential that they be a wall in the same sense as wall 1, d8. However, in all forms of the invention it is highly desirable that the deliector barrier assemblies offer no obstacle to passage of vehicles thereover when the walls are in collapsed position.

The blast receiving surfaces of the walls may be coated with any suitable insulator material, or sound dampening material wherever found desirable.

It is to be understood that various modifications may be made within the scope of the claims annexed hereto without departing from the spirit of the invention.

One such modification would be the inclusion of irregularly disposed sound bales 6i) within the channels formed by T beams S, 18 (FIG. 5). Such baflies would distort the sound of baclrblast and prevent any tendency to build-up resonance and vibration in this structure. Said baffles 60 should not, however, substantially impair the .channelling effect of the sound and blast caused by T beams 8, 18.

l claim:

l. A retractable blast delector and acoustic barrier for detlecting the blast and sound from the engines on an airplane, comprising:

(a) a pair of walls in a generally horizontal position on the ground, each having a blast receiving surface adapted to face generally toward the blast from such engines when said walls are in an erected position;

(b) means supporting said walls for movement thereof from said generally horizontal position to said erected position, and vice versa, and in which erected position one wall of said pair extends upwardly from the ground at a substantial angle relative to horizontal and said other wall extends upwardly above said one wall with their said blast receiving surfaces disposed in planes intersecting each other at an angle of less than 180 degrees, and

(c) means operatively connected with said walls for so moving them from said generally horizontal position to said erected position.

2. In a construction as defined in claim l,

(d) said one wall of said pair being below said other Wall when the walls of said pair are in said generally horizontal position and (e) said means supporting said walls for said movement thereof being adapted to support said walls in their said horizontal position below the level of the ground with the upper surface of said other wall substantially Hush with the upper surface of the ground.

3. In a construction as defined in claim l,

' (d) said means supporting said walls for said movement including wall-connecting pivot means connecting said one wall of said pair with said other wall at approximately the point of intersection between said blast receiving surfaces, and

(e) wall-rnounting pivot means at the ground mounting said one wall of said pair for swinging about a substantially horizontal axis.

4. In a construction as defined in claim 1,

(d) said blast receiving surfaces including spaced ribs extending generally upwardly relative to horizontal to restrict the lateral movement of sound waves from `said engines that engage said blast engaging surfaces.

5. In a construction as defined in claim l,

(d) the height of said one wall of said pair when in said erected position being above the level of the blast from engines of an airplane adapted to be positioned adjacent to said pair of walls.

6. ln a construction as defined in claim l,

(d) said one wall of said pair terminating at its upper edge substantially at the point of intersection of said planes when said walls are in said erected position, and the said angle between said walls at said point being a reentrant angle adapted to face the direction of the blasts to be deflected thereby, and said other wall extending over the vertically upwardly projected area of the blast receiving surface of said one wall.

7. A retractable blast deflector and acoustic barrier for deflecting the blasts and sound from airplane engines comprising:

(a) a pair of walls providing an upper wall and a lower wall disposed angnlarly relative to each other in an erected position with said lower wall having an upwardly inclined blast receiving surface for deflecting said blasts upwardly and said upper wall having a blast receiving surface inclined upwardly from the upper edge of said lower wall and oppositely to the kinclination of said first mentioned blast receiving surface,

- (b) wall supporting means adjacent to the lower end of said lower wall of said pair for pivotally supporting said lower wall for swinging downwardly to generally horizontal position,

amnesia (c) wall connecting means adjacent to the upper end of said lower wall pivotally connecting said lower wall with said upper wall for swinging said upper wall downwardly to a collapsed position overlying said lower wall when said lower wall is in said generally horizontal position,

(d) said upper wall including a downward extension thereof extending substantially to the ground when said barrier is in erected position, and

(e) power actuated means connected with the lower end of the lower wall of said pair for moving said upper and said lower walls from said collapsed position to said erected position.

8. In a construction as defined in claim 7,

(f) an upwardly opening wall receiving pit formed in the ground below the upper level of the latter (g) said wall supporting means being stationary at one end of said pit;

(lz) said upper wall and said extension thereon having an upwardly facing flat surface substantially flush with the upper surface of the ground around said pit when said upper wall and said lower wall are in said collapsed position.

9. In a construction as defined in claim 8,

(i) means supporting the lower end of said extension on the ground for horizontal reciprocable movement in a direction toward and away from said wall supporting means during movement of said walls from said erected position to said collapsed position and vice versa.

l0. In combination with a generally horizontally disposed airplane supporting station on the ground,

(a) a row of blast and acoustic barriers in substantially adjoining relation at one side of said station;

(b) each of said barriers comprising an upper wall and a lower wall disposed angularly relative to each other in an erected position with said lower wall providing an upwardly inclined blast deflecting surface extending to a height above that of the airplane engines on an airplane at said station for deecting the blast from said engines upwardly and with said upper wall inclined oppositely to said lower wall providing a blast deflecting surface inclined upwardly from the upper edge of said lower wall but in a direction opposite to the inclination of the blast receiving surface of said lower wall;

(c) wall supporting means for each barrier adjacent to the lower end of the lower wall thereof swingably supporting said lower wall for swinging downwardly to generally horizontal position,

(d) wall connecting means adjacent to the upper edge of said lower wall of each barrier hingedly connecting said lower wall with said upper wall for swinging said upper wall downwardly to a collapsed position overlying said lower wall when said lower wall is in its said generally horizontal position;

(e) a downward extension on the upper wall of each barrier extending downwardly therefrom substantially in combination thereof;

(f) power actuated means respectively connected with the said extension on each of the upper walls of each barrier for moving said upper and said lower walls from said collapsed position to said erected position;

g) means for selectively actuating said power operated means for moving any one or more of said barriers to and from erected position as desired to adapt said barriers to any size airplane at said station;

(h) and means carried by at least one of each adjacent pair of barriers movable with said upper and lower walls respectively for connecting each adjacent pair of barriers at the adjacent edges of the walls thereof against the passage of the blast therepast upon movement of the walls of any adjacent pair of barriers to their erected positions.

1l. In a construction as defined in claim l0:

(i) said row of barriers being generally arcuately extending with the reentrant angle provided by the upper and lower wall of each barrier, and the blast 5 receiving surfaces thereon, being at the concave side of the arc of said row.

l2. In a construction as defined in claim (i) means on the upper wall of each barrier providing a fiat, planar surface adapted to support wheeled ground vehicles for movement therefor when the walls of said barriers are in said collapsed position; and,

(j) means formed in the ground for receiving and positioning the walls of each barrier therein when said walls are in said collapsed position7 with the said planar surface of each upper wall substantially ush with the upper surface of the ground.

13. A retractable blast deector and acoustic barrier for deflecting the blast and sound from the engines of 2() an airplane comprising:

(a) an upper wall and a lower wall disposed angularly relative to each other in an erected position with said upper wall in an inclined position extending upwardly from the ground providing a generally downwardly directed blast receiving surface on one side thereof;

(b) said lower wall being substantially shorter than the upper wall and positioned at the side of said upper wall having said blast receiving surface and extending upwardly from the ground at an incline oppositely to the inclination of said upper wall providing a generally upwardly directed blast receiving surface;

(c) the upper end of said lower wall being at a point substantially spaced below the upper end of said upper wall and terminating substantially at the blast receiving surface of said upper wall;

(d) means for pivotally supporting the lower end of said lower wall at the ground for oscillatory movement of said upper end of said lower wall from a generally horizontal position of said lower wall to said erected position and vice versa;

(e) means pivotally connecting said lower wall at its upper end with said upper wall for swinging said upper and said lower wall relatively from said erected position to a collapsed position in which said lower wall is in said horizontal position and said upper wall is also in a substantially horizontal position overlying said lower wall;

(f) means adapted to be supported on the ground supporting the lower end of said lower wall for generally horizontal reciprocable movement upon said movement of said upper and lower walls from said erected position to said collapsed position and vice versa;

(g) power means connected with said lower end of said upper wall for so moving said lower end.

14. In a construction as defined in claim 13:

(h) a plurality of horizontally spaced upwardly eX- tending ribs projecting from the blast receiving surfaces of said upper wall and said lower wall when said walls are in said erected position providing upwardly extending channels for generally confining the blast and sound from said engines for deliection longitudinally of said channels; and,

(i) the side of said upper wall opposite to the side from which said ribs project being planar to permit the wheels of ground vehicles to pass thereover when said walls are in said collapsed position.

l5. In a construction as defined in claim 13:

(h) shock absorbing means positioned on the ground at a point intermediate the upper and lower ends of said upper wall for engagement with said walls upon movement of the latter to said collapsed position.

16. In a construction as deiined in claim 15:

(i) said shock absorbing means comprising a uid actuated member supported for generally upward movement under the influence of fluid under pressure for partially moving said walls from said collapsed position to said erected position to facilitate the movement of said walls to said erected position by said power actuated means.

17. In a construction as defined in claim 14:

(j) means disposed within said channels for distorting said blast and sound and preventing the build-up of resonance and vibration.

18. A retractable blast defiector and acoustic barrier for deiiecting the blast and sound from the engines on an airplane, comprising:

(a) a pair of walls in a generally horizontal position on the ground, each having a blast receiving surface adapted to face generally toward the blast from such engines when said walls are in an erected position;

(b) means supporting said walls for movement thereof from said generally horizontal position to said erected position, and vice versa, and in which erected position one wall of said pair extends upwardly from the ground at a substantial angle relative to horizontal and said other Wall extends upwardly above said one wall with their said blast receiving surfaces disposed in planes intersecting each other at an angle of less than 180 degrees, and

(c) means operatively connected with said Walls for so moving them from said generally horizontal position to said erected position,

(d) said means supporting said walls for said movement including wall-connecting pivot means connecting said one wall of said pair with said other Wall at approximately the point of intersection between said blast receiving surfaces, and

(e) wall-mounting pivot means at the ground mounting said one Wall of said pair for swinging about a substantially horizontal axis,

(f) said means operatively connected with said pair of walls including an extension on said other Wall of said pair projecting from said wall-connecting pivot means in a direction away from said wall mounting pivot means when said pair of walls is in said generally horizontal position, and

(g) power actuated means connected with said eX- tension movable toward said wall-mounting pivot means, whereby said pair of walls Will be moved simultaneously to said erected position upon said movement of said power actuated means toward said wall-mounting means when said pair of Walls is in said generally horizontal position.

References Cited in the le of this patent UNITED STATES PATENTS 1,925,139 Fellers Sept. 5, 1933 2,974,910 Lynn Mar. 14, 1961 3,017,146 Wagner Jan. 16, 1962 

1. A RETRACTABLE BLAST DEFLECTOR AND ACOUSTIC BARRIER FOR DEFLECTING THE BLAST AND SOUND FROM THE ENGINES ON AN AIRPLANE, COMPRISING: (A) A PAIR OF WALLS IN A GENERALLY HORIZONTAL POSITION ON THE GROUND, EACH HAVING A BLAST RECEIVING SURFACE ADAPTED TO FACE GENERALLY TOWARD THE BLAST FROM SUCH ENGINES WHEN SAID WALLS ARE IN AN ERECTED POSITION; (B) MEANS SUPPORTING SAID WALLS FOR MOVEMENT THEREOF FROM SAID GENERALLY HORIZONTAL POSITION TO SAID ERECTED POSITION, AND VICE VERSA, AND IN WHICH ERECTED POSITION ONE WALL OF SAID PAIR EXTENDS UPWARDLY FROM THE GROUND AT A SUBSTANTIAL ANGLE RELATIVE TO HORIZONTAL AND SAID OTHER WALL EXTENDS UPWARDLY ABOVE SAID ONE WALL WITH THEIR SAID BLAST RECEIVING SURFACES DISPOSED IN PLANES INTERSECTING EACH OTHER AT AN ANGLE OF LESS THAN 180 DEGREES, AND (C) MEANS OPERATIVELY CONNECTED WITH SAID WALLS FOR SO MOVING THEM FROM SAID GENERALLY HORIZONTAL POSITION TO SAID ERECTED POSITION. 